In recent years, silicon carbide has been increasingly employed as a material for a semiconductor device such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) in order to allow a higher breakdown voltage, lower loss, the use in a high-temperature environment and the like of the semiconductor device. Silicon carbide is a wide band gap semiconductor having a band gap wider than that of silicon which has been conventionally and widely used as a material for a semiconductor device. By employing the silicon carbide as a material for a semiconductor device, therefore, a higher breakdown voltage, lower on-resistance and the like of the semiconductor device can be achieved. A semiconductor device made of silicon carbide is also advantageous in that performance degradation is small when used in a high-temperature environment as compared to a semiconductor device made of silicon.
For example, WO 2012/086257 (PTD 1) describes a method of manufacturing a MOSFET comprising steps of forming an etching stop layer made of titanium on a surface of a silicon carbide substrate, forming a patterned mask layer on the etching stop layer, and then implanting ions into the silicon carbide substrate using the mask layer.